This invention relates to a keyboard musical instrument and, more particularly, to a leg for supporting a musical instrument and a keyboard musical instrument having a case supported by legs on a floor.
An acoustic piano is a typical example of the keyboard musical instrument. The acoustic piano is broken down into a keyboard, piano case and tone generating mechanism. Key actions, hammers, dampers and strings form parts of the tone generating mechanism. The tone generating mechanism is accommodated in the piano case, and is actuated with the keys for generating tones. The keys are laid on the well-known black-and-white pattern, and are essential parts of the keyboard. The keyboard is mounted on the key bed which forms a part of the piano case, and is exposed to a pianist for fingering.
FIG. 1 shows a typical example of the grand piano. Reference numerals 100, 120 and 140 designate the piano case, the keyboard and the tone generating mechanism, respectively. The piano case 100 has a case body 101 and three legs 102. A key bed 101a and a frame (not shown) define the bottom of the piano case 100, and a side board 101b extends along the periphery of the key bed 101a and the frame. Thus, the key bed 101a, the frame and the side board 101b define an inner space of the case body 101, and permits the manufacturer to install the tone generating mechanism 140 in the case body 101. A top board 108 is hinged to the side board 101b, and is opened and closed.
Three legs 102 are arranged at the vertexes of a triangle under the case body 101. Two legs 102 are arranged in substantially parallel, and are directly bolted to the key bed 101a. The remaining leg 102 is provided at the back of the two legs 102, and is fixed to the frame.
The leg 102 is not a monolithic body. Various woody parts are assembled into the leg 102 as shown in FIG. 2. A leg column 103, a leg block 104 and a caster 105 are the essential parts of the leg 102. The leg column 103 and the leg block 104 are formed of wood. The leg column 103 is an inverted prismoid. A tenon 103A is formed on the relatively wide top surface, and the caster 105 is attached to the relatively narrow bottom surface of the leg column 103. The tenon 103A is a short cylindrical projection, and two slits 103B are formed in the tenon 103A. The slits 103B extend across the upper surfaces of the tenon 103A in parallel to each other, and are exposed to the side surface of the tenon 103A. The leg block 104 has an anvil-like configuration. The leg block 104 is gently increased in thickness from both ends toward the mid portion, and a cylindrical hole 104A is formed in the mid portion. The cylindrical hole 104A is open to both of the upper and lower surfaces of the mid portion, and is equal in diameter to the tenon 103A. A pair of through-holes 104B is formed in the leg block 104. The through-holes 104B are provided on both sides of the cylindrical hole 104A. Though not shown in the drawings, threaded holes are formed in the key bed 101A, and are spaced equally to the through-holes 104B.
The leg column 103 and the leg block 104 are assembled into the leg 102 as follows. First, the worker aligns the tenon 103A with the cylindrical hole 104A, and inserts the tenon 103A into the cylindrical hole 104A. The lower surface of the leg block 104 is brought into contact with the upper surface of the leg column 103, and the upper surface of the tenon 103A becomes coplanar with the upper surface of the leg block 104. The worker pushes the edge of a wedge 107 into one of the slits 103B, and another wedge 107 into the other slit 103B. The worker strikes the wedges 107 with a hammer, by way of example. Then, the wedges 107 are implanted into the tenon 103A, and expands the slits 103B. The upper portion of the tenon 103 is pressed against the inner surface of the leg block 104, and the leg block 104 is fixed to the leg column 103.
The leg 102 thus assembled is fixed to the key bed 101a as follows. The worker aligns the through-holes 104B with the threaded holes formed in the key bed 101a. The worker inserts a bolt 106 into one of the through-holes 104B, and screws the bolt 106 into the threaded hole. Similarly, the worker inserts another bolt 106 into the other of the through-holes 104B, and screws the bolt 106 into the other threaded hole. Thus, the leg block 104 is bolted to the key bed 101a, and the leg 102 downwardly projects from the case body 101.
A problem is encountered in the prior art keyboard musical instrument in that the piano case 100 is liable to be rickety.
It is therefore an important object of the present invention to provide a keyboard musical instrument the case of which is steady and durable.
The present inventor contemplated the problem encountered in the prior art keyboard musical instrument, and noticed that the wedges 107 failed to work. The present inventor reasoned that the connection between the tenon 103A and the leg block 104 was repeatedly subjected to the bending moment. When the user wanted to relocate the prior art keyboard musical instrument, he or she pushed the case body 101, and exerted force thereon. The force gave rise to rotation of the casters 105, and the prior art keyboard musical instrument slid on the floor. However, the casters 105 were vertically spaced from the case body 101 on which the force was exerted. This resulted in that bending moment was exerted on the connection between the tenon 103A and the leg block 104. The slits 103B were strangulated, and, accordingly, the wedges 107 were partially pushed out. As a result, the tenon 103A was loosened, and the piano case 101 became rickety.
A solution had been proposed. Plural bolts were embedded into the upper portion of the leg column 103, and through-holes were formed in the leg block 104. The bolts were inserted into the through-holes, and projected over the leg block 104. The worker turned nuts on the bolts, and held the bolts in their places with nuts. However, the solution was costly and risky. Time and labor were consumed in the implantation of the bolts into the leg column 103. This resulted in the high production cost. Moreover, the leg column 103 was not thick enough to receive the plural bolts. When the worker compelled the leg column 103 to receive plural bolts, extremely thin peripheral portion took place between the implanted bolt and the outer surface of the leg column 103, and was liable to be broken under the application of the bending moment. The present inventor concluded that a monolithic leg was preferable. However, a monolithic leg shaped from a piece of wood was extremely expense.
To accomplish the object, the present invention proposes to form laminated members into a core of a leg.
In accordance with one aspect of the present invention, there is provided a leg incorporated in a keyboard musical instrument, and the leg comprises plural plates laminated on one another and assembled into a core and a coupling means for fixing the core to a body of the keyboard musical instrument.
In accordance with another aspect of the present invention, there is provided a keyboard musical instrument comprising a case having an inner space, a keyboard mounted on the case and having keys assigned notes of a scale, a tone generating mechanism accommodated in the inner space and connected to the keyboard for generating tones with the notes and plural legs, and each of the legs includes plural plates laminated on one another and assembled into a core and a coupling means for fixing the core to the body.